Preparation and surface- active properties of polyoxyethylene-glycol (600) monoesters of fatty acids

Polyoxyethyleneglycol (PEG-600) monoesters of undecylenic, lauric, myristic, palmitic, stearic, oleic, ricinoleic and 12-hydroxystearic acids were prepared in 80-85% yield by reacting PEG with boric acid, esterifying the resultant borate with fatty acid, and selectively hydrolyzing the borate ester; their surface active properties were evaluated. Increase in acyl chain length increased the surface tension. The presence of a double bond or hydroxyl group in C₁₈ series improved the wetting and emulsifying proper-ties. Unsaturation in the fatty acid chain reduced the foaming power.     

Flash pyrolysis of coal: effect of nitrogen,argon and other atmospheres in increasing olefin concentration and its significance on the mechanism of coal pyrolysis

Samples of three Indian coals, of widely differing origin and rank, were subjected to flash pyrolysis at a temperature of about 1150 °C for 30 s in vacuo, and under atmospheres of nitrogen, argon, ammonia, and perdeuterobenzene. The gaseous products of the pyrolyses were analysed by infra-red and mass spectroscopy and by gas chromatography. Observed variations in gas compositions are discussed relative to the possible mode of influence by the pyrolytic atmospheres. It would appear that the pyrolytic atmosphere is an important factor in determining the composition of the pyrolysis products; the influence of nitrogen, argon and perdeuterobenzene is a physical one, leading especially to higher yields of olefins.     

Photocrosslinking of stilbene-modified polymers

The reactions of trans-2,5-dimethoxy-4′-aminostilbene with poly(maleic anhydride-co-methylvinyl ether) and trans-2,5-dimethoxy-4′-isocyanatostilbene with poly(oxy-1,4-phenyleneisopropylidene:1,4-phenyleneoxy-2-hydroxytrimethylene) yield polymeric systems which undergo rapid crosslinking upon short exposure to ultraviolet light. The extent of photocrosslinking as a function of exposure time was determined by the decrease of the trans-stilbene ultraviolet absorption at 350 nm.     

Grafting onto polyester fibers. III. Electrokinetic properties of acrylic acid and acrylonitrile-grafted polyester fibers in the presence of cationic dyes

The electrokinetic properties such as zeta potential, surface charge density, and surface conductivity of polyester fibers grafted with acrylic acid and acrylonitrile were measured when cationic dye solutions were streamed through. The presence of the cationic dyes on the surface of the fibers and their specific adsorption at the carboxylic groups in the acrylic acid graft copolymer produce lowering of zeta potential. The decrease in surface charge density as the percent graft increases is due to the decrease in surface area of the fibers due to the adsorption of the cationic dyes. The same trend is observed with acrylonitrile-grafted fibers. The surface conductivity of the acrylonitrile-grafted polyester fibers increases with increase in dye concentration of the streaming solution. The results for the 27.4% grafted sample differed from those of the 7.32% and 12.1% grafts, which is indicative of the formation of a three-dimensional network causing change in both the physical structure as well as the chemical nature of the surface of the substrate.     

Water Desalination a perspective for membrane processes in India

A crying need of the day in India is to supply safe drinking water to its villages, towns and cities. Though the urban needs are partially met by organized water supply schemes, acute water shortages are felt at various times in this sector also with the expanding industrialization of the country. In many areas of arid and semi-arid regions, only brackish waters are available which are unfit for human consumption.Research and development effort at CSMCRI on the two membrane processes, reverse osmosis and electrodialysis, during the past decade has been reviewed. Some of the current activities in the rural sector and the future potential for these two processes in tackling the pressing needs of potable water to the rural masses in India are outlined. In the industrial sector, these two processes have immense potentialities in pollution abatement and water reuse.     

Mesh-free canonical tensor products for six-dimensional density matrix: computation of kinetic energy

The computation of a six-dimensional density matrix is the crucial step for the evaluation of kinetic energy in electronic structure calculations. For molecules with heavy nuclei, one has to consider a very refined mesh in order to deal with the nuclear cusps. This leads to high computational time and needs huge memory for the computation of the density matrix. To reduce the computational complexity and avoid discretization errors in the approximation, we use mesh-free canonical tensor products in electronic structure calculations. In this paper, we approximate the six-dimensional density matrix in an efficient way and then compute the kinetic energy. Accuracy is examined by comparing our computed kinetic energy with the exact computation of the kinetic energy.     

Efficient Design of Rounding Based Static Segment Imprecise Multipliers for Error Tolerance Application

Journal of Electronic Testing - Error-Tolerant applications regularly accomplish more data adaption. Approximate computing is one of the optimum strategies for data manipulation in several...